Substrate polishing apparatus

ABSTRACT

A substrate polishing apparatus includes a polishing table  30  having a polishing surface  10  in the upper surface, a substrate holding portion  31  that holds a substrate W having a surface to be polished in the lower surface, and a holding portion cover  36  that covers the outer side of the substrate holding portion  31 . Between the lower portion of the holding portion cover  36  and the upper surface of the polishing table  30 , a gap portion for intake  37  is provided, and in the upper portion of the holding portion cover  36 , a pipe for exhaust  39  connected to an exhaust mechanism  38  is provided. By operating the exhaust mechanism  38 , a rising air current from the gap portion  37  toward the pipe  39  is formed between the outer surface of the substrate holding portion  31  and the inner surface of the holding portion cover  36.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a division of U.S. patent application Ser. No. 14/699,075, filedApr. 29, 2015, which claims the benefit of Japanese Priority PatentApplications 2014-094137 filed on Apr. 30, 2014 and 2014-111263 filed onMay 29, 2014, the entire contents of which are incorporated herein byreference.

FIELD

This technology relates to a substrate polishing apparatus that polishesa substrate surface (surface to be polished), and particularly to asubstrate polishing apparatus suitable for a situation where a hazardousgas is generated.

BACKGROUND AND SUMMARY

Conventionally, a hazardous liquid chemical may be used to polish acompound semiconductor substrate (wafer). For example, for an SiCsubstrate, HF may be used. Also, For a GaAs substrate, harmful arsenicmay be mixed into a polishing waste liquid. Thus, in a conventionalsubstrate polishing apparatus, a polishing environment is locallyisolated and exhaust is carried out by a down flow system, preventingthe leakage of a toxic substance to the outside. For example, JapanesePatent Laid-Open No. 2008-166709 describes such a technology.

However, in the conventional substrate polishing apparatus, it isnecessary to improve tightness and enhance an exhaust volume in eachportion of the apparatus, so that it becomes necessary to makesignificant design changes. Therefore, it has been desired to develop anapparatus capable of preventing the diffusion of a hazardous gaseffectively without a significant design change.

A substrate polishing apparatus of one embodiment includes a polishingtable having a polishing surface in an upper surface, a substrateholding portion that holds a substrate having a surface to be polishedin a lower surface and presses the surface to be polished of thesubstrate against the polishing surface of the polishing table to polishthe surface to be polished of the substrate, and a holding portion coverthat covers an outer side of the substrate holding portion, in whichbetween a lower portion of the holding portion cover and the uppersurface of the polishing table, a gap portion for intake is provided,and in an upper portion of the holding portion cover, a pipe for exhaustconnected to an exhaust mechanism is provided, and by operating theexhaust mechanism, a rising air current from the gap portion toward thepipe is formed between an outer surface of the substrate holding portionand an inner surface of the holding portion cover.

A substrate polishing apparatus of another embodiment includes arotating polishing table, a substrate holding portion that holds asubstrate and presses the substrate against the polishing table topolish the substrate, and a local exhaust mechanism whose intake head isdisposed near the substrate holding portion, in which the intake head isdisposed on a downstream side of the substrate holding portion in arotation direction of the polishing table.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view illustrating a whole configuration of a substrateprocessing apparatus in a first embodiment;

FIG. 2 is a perspective view illustrating a structure of a swingtransporter in the first embodiment;

FIG. 3A is a plan view illustrating a cleaning portion in the firstembodiment, and FIG. 3B is a side view illustrating the cleaning portionin the first embodiment;

FIG. 4 is an illustration showing a schematic configuration of asubstrate polishing apparatus in the first embodiment;

FIG. 5 is an illustration showing a main configuration of the substratepolishing apparatus in the first embodiment;

FIGS. 6A and 6B are views illustrating examples of a holding portioncover in the first embodiment;

FIGS. 7A-7D are views illustrating examples of an inlet of a pipe forexhaust in the first embodiment;

FIG. 8 is a view illustrating a configuration of an air currentgenerating mechanism in the first embodiment;

FIGS. 9A and 9B are views illustrating examples of the air currentgenerating mechanism in the first embodiment;

FIG. 10 is a view illustrating a configuration of a shielding mechanismin the first embodiment;

FIGS. 11A and 11B are views illustrating examples of the shieldingmechanism in the first embodiment;

FIG. 12 is an illustration showing a schematic configuration of asubstrate polishing apparatus in a second embodiment;

FIG. 13 is a plan view illustrating a main configuration of thesubstrate polishing apparatus in the second embodiment;

FIG. 14 is a side view illustrating the main configuration of thesubstrate polishing apparatus in the second embodiment;

FIG. 15 is an illustration showing a schematic configuration of anexample of variation of the second embodiment;

FIG. 16 is a plan view illustrating a main configuration of a substratepolishing apparatus in a third embodiment;

FIG. 17 is a side view illustrating the main configuration of thesubstrate polishing apparatus in the third embodiment; and

FIG. 18 is a plan view illustrating a main configuration of an exampleof variation of the third embodiment.

DETAILED DESCRIPTION OF NON-LIMITING EXAMPLE EMBODIMENTS

Now, a substrate polishing apparatus of an embodiment will be describedbelow. Note that the embodiment to be described below illustrates oneexample where this technology is implemented, and this technology shouldnot be limited to a specific configuration to be described below. Whenthis technology is implemented, a specific configuration may beappropriately adopted depending on an embodiment.

A substrate polishing apparatus of one embodiment includes a polishingtable having a polishing surface in an upper surface, a substrateholding portion that holds a substrate having a surface to be polishedin a lower surface and presses the surface to be polished of thesubstrate against the polishing surface of the polishing table to polishthe surface to be polished of the substrate, and a holding portion coverthat covers an outer side of the substrate holding portion, in whichbetween a lower portion of the holding portion cover and the uppersurface of the polishing table, a gap portion for intake is provided,and in an upper portion of the holding portion cover, a pipe for exhaustconnected to an exhaust mechanism is provided, and by operating theexhaust mechanism, a rising air current from the gap portion toward thepipe is formed between an outer surface of the substrate holding portionand an inner surface of the holding portion cover.

According to this configuration, even if a hazardous gas is generatedbetween a polishing surface and a surface to be polished when asubstrate is polished, then the holding portion cover that covers theouter side of the substrate holding portion can prevent the hazardousgas from diffusing from the site of generation to the environment. Insuch a situation, the gas diffusion can be effectively prevented nearthe site of generation of the hazardous gas. And, this can beimplemented by using such a comparatively simple configuration as theholding portion cover and a significant design change is notnecessitated. Furthermore, once the exhaust mechanism is operated, airis sucked in through a gap portion between the lower portion of theholding portion cover and the upper surface of the polishing table andthe air is exhausted through a pipe provided in the upper portion of theholding portion cover, then a rising air current is formed between theouter surface of the substrate holding portion and the inner surface ofthe holding portion cover. Accordingly, the gas can be prevented fromleaking out through the gap portion in the lower portion of the holdingportion cover to the environment, and the gas can be safely exhaustedthrough the pipe in the upper portion of the holding portion cover.

Also, in the above substrate polishing apparatus, the holding portioncover is movable between a covering position at which the holdingportion cover comes close to the substrate holding portion to cover theouter side of the substrate holding portion and a non-covering positionat which the holding portion is separated from the substrate holdingportion and does not cover the outer side of the substrate holdingportion, and when a surface to be polished of a substrate is polished,the holding portion cover may be placed at the covering position, andwhen a surface to be polished of a substrate is not polished, theholding portion cover may be placed at the non-covering position.

According to this configuration, when the holding portion cover isrequired (when a hazardous gas is generated), the holding portion coveris placed at the used position, so that the hazardous gas can beprevented from diffusing to the environment. On the one hand, when theholding portion cover is not required (when a hazardous gas is notgenerated), the holding portion cover is placed at the non-usedposition, so that interference with other components can be prevented.

Also, in the above substrate polishing apparatus, the holding portioncover may be configured to cover the entire circumference of thesubstrate holding portion.

According to this configuration, the holding portion cover that coversthe entire circumference of the substrate holding portion can prevent ahazardous gas from diffusing to the environment. In such a situation,the diffusion of the gas can be prevented throughout the entirecircumference without leak.

Also, in the above substrate polishing apparatus, the holding portioncover may be configured to partially cover the circumference of thesubstrate holding portion.

According to this configuration, the holding portion cover thatpartially covers the circumference of the substrate holding portion canprevent a hazardous gas from diffusing to the environment. In such asituation, the diffusion of the gas can be partially preventedeffectively (only the necessary portion).

Also, in the above substrate polishing apparatus, in the substrateholding portion, a rising air current generating mechanism thatgenerates a rising air current between the outer surface of thesubstrate holding portion and the inner surface of the holding portioncover due to rotation of the substrate holding portion may be provided.

According to this configuration, once the substrate holding portionrotates, the rising air current generating mechanism generates a risingair current between the outer surface of the substrate holding portionand the inner surface of the holding portion cover. Providing the risingair current generating mechanism in such a manner can assist in formingthe rising air current between the outer surface of the substrateholding portion and the inner surface of the holding portion cover.

Furthermore, the above substrate polishing apparatus may further includea table cover that covers the outer side of the polishing table, asecond gap portion for intake provided between the polishing table andthe table cover, and a second pipe for exhaust connected to the exhaustmechanism and provided in the lower portion of the table cover, and inthe polishing table, a descending air current generating mechanism thatgenerates a descending air current between the outer surface of thepolishing table and the inner surface of the table cover due to rotationof the polishing table may be provided.

According to this configuration, once the exhaust mechanism is operated,air is sucked in through the second gap portion between the polishingtable and the table cover, and the air is exhausted through a pipeprovided in the lower portion of the table cover, forming a descendingair current between the outer surface of the polishing table and theinner surface of the table cover. The table cover that covers the outerside of the polishing table can prevent a hazardous gas from diffusingto the environment, and the gas can be safely exhausted through the pipein the lower portion of the table cover. And, in such a situation, oncethe polishing table rotates, the descending air current generatingmechanism generates a descending air current between the outer surfaceof the polishing table and the inner surface of the table cover.Providing the descending air current generating mechanism in such amanner can assist in forming the descending air current between thepolishing table and the table cover.

Also, the above substrate polishing apparatus may further include ashielding mechanism that covers the outer side of the holding portioncover that covers the outer side of the substrate holding portion andthe outer side of the polishing table.

According to this configuration, because the shielding mechanism coversthe outer side of the holding portion cover (the outer side of theholding portion cover that covers the outer side of the substrateholding portion) and the outer side of the polishing table, a functionthat prevents a hazardous gas from diffusing to the environment can beimproved.

Furthermore, in the above substrate polishing apparatus, the pipe mayfurther include a gas-liquid separating mechanism.

According to this configuration, even if a liquid is mixed into a gaswhen the gas is sucked in through the gap portion between the lowerportion of the holding portion cover and the upper surface of thepolishing table, the gas-liquid separating mechanism can separate thegas from the liquid, so that the gas (separated from the liquid) can beappropriately exhausted.

A substrate polishing apparatus of another embodiment includes arotating polishing table, a substrate holding portion that holds asubstrate and presses the substrate against the polishing table topolish the substrate, and a local exhaust mechanism whose intake head isdisposed near the substrate holding portion, in which the intake head isdisposed on a downstream side of the substrate holding portion in arotation direction of the polishing table.

According to this configuration, even if a hazardous gas is generatedwhen a substrate is polished, the intake head disposed near thesubstrate holding portion can suck in the gas effectively. In such asituation, because the intake head is disposed on the downstream side inthe rotation direction of the polishing table, the gas made to flow byan air current (swirl flow) generated from rotation of the polishingtable can be sucked in effectively. In this way, such a comparativelysimple configuration as the intake head can prevent the diffusion of ahazardous gas effectively near the site of generation of the gas and asignificant design change is not necessitated.

Also, in the above substrate polishing apparatus, an intake air speed ofthe intake head may be set to be higher than a rotation speed of thepolishing table.

A speed at which a gas is made to flow by an air current (swirl flow)generated from rotation of the polishing table is thought to be aboutequal to (or not greater than) the rotation speed of the polishingtable. In such a situation, because the intake air speed of the intakehead is set to be higher than the rotation speed of the polishing table,a gas made to flow by the air current (swirl flow) generated from therotation of the polishing table can be preferably sucked in depending onthe speed at which the gas is made to flow.

Also, in the above substrate polishing apparatus, the intake headincludes a plurality of inlets arrayed in a radial direction of thepolishing table, in which an intake air speed of the inlet of theplurality of inlets on the outer side in the radial direction may be setto be higher than that of the inlet on the inner side in the radialdirection.

According to this configuration, the plurality of inlets of the intakehead can suck in a hazardous gas generated when a substrate is polished.Because the rotation speed of the polishing table on the outer side inthe radial direction is higher than that on the inner side in the radialdirection, the speed at which a gas is made to flow by the air current(swirl flow) generated from the rotation of the polishing table isthought to be higher on the outer side in the radial direction than onthe inner side in the radial direction (there is a difference along theradial direction). In such a situation, because the plurality of inletsis arrayed in the radial direction of the polishing table and the intakeair speed of the inlet on the outer side in the radial direction is setto be higher than that on the inner side in the radial direction, a gasmade to flow by the air current (swirl flow) generated from the rotationof the polishing table can be preferably sucked in depending on adifference in speed at which the gas is made to flow (a difference alongthe radial direction).

First Embodiment

Now, a substrate polishing apparatus of a first embodiment will bedescribed below with reference to the drawings. In this embodiment, asubstrate processing apparatus will be illustrated in which a substrateis polished by using chemical mechanical polishing (CMP).

FIG. 1 is a plan view illustrating a whole configuration of thesubstrate processing apparatus in this embodiment. As shown in FIG. 1,this substrate processing apparatus includes a housing 1 having an aboutrectangular shape, in which the inside of the housing 1 is partitionedinto a load/unload portion 2, a polishing portion 3 and a cleaningportion 4 by partition walls 1 a, 1 b. These load/unload portion 2,polishing portion 3 and cleaning portion 4 are each assembledindependently. Also, the substrate processing apparatus includes acontrol portion 5 that controls substrate processing operation.

The load/unload portion 2 includes two or more (four in this embodiment)front load portions 20 on which a wafer cassette that stocks many wafers(substrate) is mounted. These front load portions 20 are disposedadjacent to the housing 1 and arrayed along a width direction of thesubstrate processing apparatus (direction perpendicular to alongitudinal direction). The front load portion 20 is configured so thatan open cassette, an SMIF (Standard Manufacturing Interface) pod or aFOUP (Front Opening Unified Pod) can be mounted thereon. Here, the SMIFand the FOUP are a closed container in which the wafer cassette ishoused and whose environment can be kept independently of the externalspace by using a partition wall for covering the container.

Also, in the load/unload portion 2, a traveling mechanism 21 is laidalong the array of the front load portions 20, and on the travelingmechanism 21, two transfer robots (loader) 22 movable along an arraydirection of the wafer cassette are installed. The transfer robot 22 canmove on the traveling mechanism 21 to access the wafer cassette mountedon the front load portion 20. Each transfer robot 22 has two handles oneabove the other, and the upper hand is used to return a processed waferto the wafer cassette and the lower hand is used to take out a waferprior to processing from the wafer cassette, and the upper and lowerhands can be used properly and separately. Furthermore, the lower handof the transfer robot 22 is configured capable of rotating around itsshaft center to invert a wafer.

Because the load/unload portion 2 is a region required to be kept at thecleanest state, the inside of the load/unload portion 2 is alwaysmaintained at a pressure higher than that of any of the outside of thesubstrate processing apparatus, the polishing portion 3 and the cleaningportion 4. The polishing portion 3 is the dirtiest region because aslurry is used therein as a polishing solution. Thus, a negativepressure is formed in the polishing portion 3 and the pressure ismaintained lower than an inner pressure of the cleaning portion 4. Theload/unload portion 2 includes a filter fan unit (not shown) having aclean air filter such as an HEPA filter, an ULPA filter or a chemicalfilter, and from this filter fan unit, a clean air in which particles, atoxic vapor and a toxic gas are removed always blows out.

The polishing portion 3 is a region where a wafer is polished (flattenedout) and includes a first polishing unit 3A, a second polishing unit 3B,a third polishing unit 3C and a fourth polishing unit 3D. These firstpolishing unit 3A, second polishing unit 3B, third polishing unit 3C andfourth polishing unit 3D, as shown in FIG. 1, are arrayed along thelongitudinal direction of the substrate processing apparatus. In thepolishing portion 3, a wafer surface (surface to be polished) ispolished to remove a metal film formed on the surface to be polished.

As shown in FIG. 1, the first polishing unit 3A includes a polishingtable 30A on which a polishing pad 10 having a polishing surface isattached, a top ring 31A that holds a wafer and presses the waferagainst the polishing pad 10 on the polishing table 30A to polish thewafer, a polishing solution supply nozzle 32A for supplying a polishingsolution and a dressing solution (for example, purified water) to thepolishing pad 10, a dresser 33A for dressing the polishing surface ofthe polishing pad 10, and an atomizer 34A that sprays a mixed fluid of aliquid (for example, purified water) and a gas (for example, nitrogengas) or a liquid (for example, purified water) in a mist onto thepolishing surface.

Similarly, the second polishing unit 3B includes a polishing table 30Bon which the polishing pad 10 is attached, a top ring 31B, a polishingsolution supply nozzle 32B, a dresser 33B and an atomizer 34B. Also, thethird polishing unit 3C includes a polishing table 30C on which thepolishing pad 10 is attached, a top ring 31C, a polishing solutionsupply nozzle 32C, a dresser 33C and an atomizer 34C. Furthermore, thefourth polishing unit 3D includes a polishing table 30D on which thepolishing pad 10 is attached, a top ring 31D, a polishing solutionsupply nozzle 32D, a dresser 33D and an atomizer 34D.

Because the first polishing unit 3A, the second polishing unit 3B, thethird polishing unit 3C and the fourth polishing unit 3D have anidentical configuration to each other, the first polishing unit 3A willbe described below.

FIG. 2 is a perspective view for schematically illustrating the firstpolishing unit 3A. The top ring 31A is supported by a top ring shaft. Onthe upper surface of the polishing table 30A, the polishing pad 10 isstuck, and the upper surface of this polishing pad 10 provides apolishing surface that polishes a wafer W. Note that instead of thepolishing pad 10, bonded abrasive grains can be used. The top ring 31Aand the polishing table 30A, as shown by the arrows, are configured torotate around their shaft centers, respectively. A wafer W is held onthe lower surface of the top ring 31A by vacuum suction. On polishing, apolishing solution is supplied from the polishing solution supply nozzle32A to the polishing surface of the polishing pad 10, and the wafer W tobe polished is pushed against the polishing surface by the top ring 31Aand the wafer is polished.

Next, a transport mechanism for transporting a wafer will be described.As shown in FIG. 1, adjacent to the first polishing unit 3A and thesecond polishing unit 3B, a first linear transporter 6 is disposed. Thisfirst linear transporter 6 is a mechanism that transports a waferbetween four transport positions along the direction in which thepolishing units 3A, 3B are arrayed (a first transport position TP1, asecond transport position TP2, a third transport position TP3 and afourth transport position TP4 in the order from the load/unload portionside).

Also, adjacent to the third polishing unit 3C and the fourth polishingunit 3D, a second linear transporter 7 is disposed. This second lineartransporter 7 is a mechanism that transports a wafer between threetransport positions along the direction in which the polishing units 3C,3D are arrayed (a fifth transport position TP5, a sixth transportposition TP6 and a seventh transport position TP7 in the order from theload/unload portion side).

A wafer is transported to the polishing units 3A, 3B by the first lineartransporter 6. As stated above, the top ring 31A of the first polishingunit 3A moves between a polishing position and the second transportposition TP2 by swing motion of a top ring head. Accordingly,delivery/receipt of a wafer to/from the top ring 31A are carried out atthe second transport position TP2. Similarly, the top ring 31B of thesecond polishing unit 3B moves between a polishing position and thethird transport position TP3 and delivery/receipt of a wafer to/from thetop ring 31B are carried out at the third transport position TP3. Thetop ring 31C of the third polishing unit 3C moves between a polishingposition and the sixth transport position TP6 and delivery/receipt of awafer to/from the top ring 31C are carried out at the sixth transportposition TP6. The top ring 31D of the fourth polishing unit 3D movesbetween a polishing position and the seventh transport position TP7 anddelivery/receipt of a wafer to/from the top ring 31D are carried out atthe seventh transport position TP7.

At the first transport position TP1, a lifter 11 for receiving a waferfrom the transfer robot 22 is disposed. A wafer is delivered from thetransfer robot 22 to the first linear transporter 6 through this lifter11. A shutter (not shown) is provided in the partition wall 1 a to besituated between the lifter 11 and the transfer robot 22, and ontransporting a wafer, the shutter is opened so that the wafer isdelivered from the transfer robot 22 to the lifter 11. Also, between thefirst linear transporter 6, the second linear transporter 7 and thecleaning portion 4, a swing transporter 12 is disposed. This swingtransporter 12 has a hand movable between the fourth transport positionTP4 and the fifth transport position TP5, and the swing transporter 12carries out delivery of a wafer from the first linear transporter 6 tothe second linear transporter 7. The second linear transporter 7transports a wafer to the third polishing unit 3C and/or the fourthpolishing unit 3D. Also, a wafer polished in the polishing portion 3 istransported to the cleaning portion 4 via the swing transporter 12.

FIG. 3A is a plan view illustrating the cleaning portion 4 and FIG. 3Bis a side view illustrating the cleaning portion 4. In the cleaningportion 4, a wafer W polished in the polishing portion 3 is washed anddried. As shown in FIGS. 3A and 3B, the cleaning portion 4 ispartitioned into a first washing room 190, a first transport room 191, asecond washing room 192, a second transport room 193 and a drying room194. In the first washing room 190, an upper primary washing module 201Aand a lower primary washing module 201B arrayed along a longitudinaldirection are disposed. The upper primary washing module 201A isdisposed above the lower primary washing module 201B. Similarly, in thesecond washing room 192, an upper secondary washing module 202A and alower secondary washing module 202B arrayed along the longitudinaldirection are disposed. The upper secondary washing module 202A isdisposed above the lower secondary washing module 202B. The primary andsecondary washing modules 201A, 201B, 202A and 202B are a washer thatwashes a wafer by using a wash solution. These primary and secondarywashing modules 201A, 201B, 202A and 202B are arrayed along a verticaldirection, providing an advantage that a footprint area is small.

Between the upper secondary washing module 202A and the lower secondarywashing module 202B, a temporary placing table 203 for a wafer isprovided. In the drying room 194, an upper drying module 205A and alower drying module 205B arrayed along the longitudinal direction aredisposed. These upper drying module 205A and lower drying module 205Bare isolated from each other. In the upper portion of the upper dryingmodule 205A and the lower drying module 205B, filter fan units 207, 207are provided to supply a clean air into the drying modules 205A, 205B,respectively. The upper primary washing module 201A, the lower primarywashing module 201B, the upper secondary washing module 202A, the lowersecondary washing module 202B, the temporary placing table 203, theupper drying module 205A and the lower drying module 205B are fixed on aframe not shown by using a bolt or the like.

In the first transport room 191, a first transfer robot 209 movable upand down is disposed, and in the second transport room 193, a secondtransfer robot 210 movable up and down is disposed. The first transferrobot 209 and the second transfer robot 210 are movably supported bysupport axes 211, 212 extending along a longitudinal direction,respectively. The first transfer robot 209 and the second transfer robot210 have a drive mechanism such as a motor therein, and are movable upand down along the support axes 211, 212. The first transfer robot 209,similarly to the transfer robot 22, has two hands one above the other.In the first transfer robot 209, as shown by the dashed lines in FIG.3A, the lower hand is disposed at a position accessible to a temporaryplacing table 180. When the lower hand of the first transfer robot 209accesses the temporary placing table 180, a shutter (not shown) providedin the partition wall 1 b is opened.

The first transfer robot 209 operates to transport a wafer W between thetemporary placing table 180, the upper primary washing module 201A, thelower primary washing module 201B, the temporary placing table 203, theupper secondary washing module 202A and the lower secondary washingmodule 202B. When a wafer prior to washing (a wafer to which a slurryadheres) is transported, the first transfer robot 209 uses the lowerhand to transport it, and when a washed wafer is transported, the upperhand is used. The second transfer robot 210 operates to transport awafer W between the upper secondary washing module 202A, the lowersecondary washing module 202B, the temporary placing table 203, theupper drying module 205A and the lower drying module 205B. The secondtransfer robot 210 transports only the washed wafer and accordingly hasonly one hand. The transfer robot 22 shown in FIG. 1 uses its upper handto take out a wafer from the upper drying module 205A or the lowerdrying module 205B and returns the wafer to the wafer cassette. When theupper hand of the transfer robot 22 accesses the drying modules 205A,205B, a shutter (not shown) provided in the partition wall 1 a isopened.

Next, a characteristic configuration of a substrate polishing apparatusof this embodiment will be described with reference to the drawings.FIG. 4 is an illustration showing a schematic configuration of thesubstrate polishing apparatus of this embodiment and FIG. 5 is anillustration showing a main configuration of the substrate polishingapparatus of this embodiment.

As shown in FIGS. 4 and 5, the substrate polishing apparatus of thisembodiment includes a polishing table 30 having a polishing surface 10in the upper surface, a table cover 35 that covers the outer side of thepolishing table 30, a top ring 31 that holds a wafer W having a surfaceto be polished in the lower surface and a top ring cover 36 that coversthe outer side of the top ring 31. The polishing surface 10 includes,for example, a polishing pad. The top ring 31 presses the surface to bepolished of the held wafer W (lower surface in FIGS. 4 and 5) againstthe polishing surface 10 of the polishing table 30 to polish the surfaceto be polished of the wafer W.

In such a situation, between the lower portion of the top ring cover 36and the upper surface of the polishing table 30, a gap portion forintake 37 is provided, and in the upper portion of the top ring cover36, a pipe for exhaust 39 connected to an exhaust mechanism 38 isprovided. By operating the exhaust mechanism 38, a rising air currentfrom the gap portion 37 toward the pipe 39 (upward from below) is formedbetween the outer surface of the top ring 31 and the inner surface ofthe top ring cover 36 (see FIG. 5).

Also, between the polishing table 30 and the table cover 35, a secondgap portion for intake 40 is provided, and in the lower portion of thetable cover 35, a second pipe for exhaust 41 connected to the exhaustmechanism 38 is provided. By operating the exhaust mechanism 38, adescending air current downward from above is formed between thepolishing table 30 and the table cover 35 (see FIG. 5).

Note that the pipe for exhaust 39 may be connected to a duct having anexhaust function, and also the pipe for exhaust 39 may be provided witha blower driven by an electric motor or the like. That is, as theexhaust mechanism 38, the duct having an exhaust function or the blowerdriven by an electric motor or the like can be used. Also, the pipe forexhaust 39 includes a gas-liquid separating mechanism 42 (see FIG. 4).Note that also the second pipe 41 may include the gas-liquid separatingmechanism 42.

The top ring cover 36 may be movable between a covering position(position at which the top ring cover 36 comes close to the top ring 31to cover the circumference of the top ring 31) and a non-coveringposition (position at which it is separated from the top ring 31 anddoes not cover the circumference of the top ring 31). When a surface tobe polished of a wafer W is polished (when exhaust is required), the topring cover 36 is placed at a used position to exhaust a generated gaseffectively. On the one hand, when a surface to be polished of a wafer Wis not polished (for example, when exhaust is not required, such as whenthe top ring 31 is moved), the top ring cover 36 is placed at a non-usedposition, allowing interference with the top ring 31 to be avoided.

FIGS. 6A and 6B are views illustrating examples of the top ring cover 36in this embodiment. As shown in FIG. 6A, the top ring cover 36 can beconfigured to cover the entire circumference of the top ring 31 when thetop ring cover 36 is placed at the covering position. In such asituation, a cover shape of the top ring cover 36 is split so that theentire circumference can be easily covered. Alternatively, as shown inFIG. 6B, the top ring cover 36 can be configured to partially cover thecircumference of the top ring 31 when the top ring cover 36 is placed atthe covering position. For example, when a swirl flow is generated abovethe polishing table 30, only in the portion corresponding to thedownstream of the gas flow, the top ring cover 36 may be provided.

FIGS. 7A-7D are views illustrating examples of an inlet of the pipe forexhaust 39 in this embodiment. As shown in FIG. 7A, the inlet of thepipe for exhaust 39 may have a box-like shape. Also, as shown in FIG.7B, the inlet of the pipe for exhaust 39 may have a shape that fits theouter circumference of the top ring 31. Furthermore, as shown in FIG.7C, the inlet of the pipe for exhaust 39 may have a box-like shapeformed by coupling a plurality of cylindrical components with eachother. Also, as shown in FIG. 7D, the inlet of the pipe for exhaust 39may have both of a shape formed by coupling a plurality of cylindricalcomponents with each other and a shape that fits the outer circumferenceof the top ring 31.

FIGS. 8, 9A and 9B are views illustrating examples of an air currentgenerating mechanism in this embodiment. As shown in FIGS. 8, 9A and 9B,the top ring 31 includes a rising air current generating mechanism 43that generates a rising air current between the outer surface of the topring 31 and the inner surface of the top ring cover 36 due to rotationof the top ring 31. Also, the polishing table 30 includes a descendingair current generating mechanism 44 that generates a descending aircurrent between the outer surface of the polishing table 30 and theinner surface of the table cover 35 due to rotation of the polishingtable 30.

The air current generating mechanisms (rising air current generatingmechanism 43 and descending air current generating mechanism 44) are,for example, a blade mechanism including a fin, a thread groove, or thelike. The rising air current generating mechanism 43 may be provided inthe outer peripheral surface of the top ring 31 (see FIG. 8). Also, therising air current generating mechanism 43 may be provided in the uppersurface of the top ring 31 (see FIG. 9A), or on a rotation axis of thetop ring 31. Similarly, the descending air current generating mechanism44 may be provided in the outer peripheral surface of the polishingtable 30 (see FIG. 8). Also, the descending air current generatingmechanism may be provided in the lower surface of the polishing table 30(see FIG. 9A), or on a rotation axis of the polishing table 30 (see FIG.9B).

Note that the top ring cover 36 may be rotatable independently of thetop ring 31, and in the inner peripheral surface of the top ring cover36, the rising air current generating mechanism 43 may be provided, butnot shown here. Similarly, the table cover 35 may be rotatableindependently of the polishing table 30, and in the inner peripheralsurface of the table cover 35, the descending air current generatingmechanism 44 may be provided.

FIGS. 10, 11A and 11B are views illustrating examples of a shieldingmechanism 45 in this embodiment. As shown in FIG. 10, the shieldingmechanism 45 is configured to cover the outer side of the top ring cover36 (the outer side of the top ring 31) and the outer side of thepolishing table 30. This shielding mechanism 45 is disposed between aPOS room wall and a maintenance door 47, and the top ring 31 and thepolishing table 30. In the shielding mechanism 45, an operable openingportion 46 is provided so that carry-in/carry-out of a wafer W andmaintenance are not blocked. Note that the shielding mechanism 45 isinstalled so as not to block another opening portion provided in the POSroom (another opening portion for carry-in/carry-out of a wafer W andmaintenance, not shown). When a contaminant adheres to the inner surfaceof the shielding mechanism 45, if the shielding mechanism 45 is put awayso that the inner surface of the shielding mechanism 45 is covered, thenthe contaminated surface can be prevented from being exposed to amaintenance worker.

For example, the shielding mechanism 45 can be a vinyl curtain having aheight from a ceiling surface of the POS room to a floor surface (seeFIG. 10). Also, the shielding mechanism 45 can be panels or bellowsdeployable at the point of use (see FIGS. 11A and 11B). It is desirablethat a material of the shielding mechanism 45 should have transparenceallowing the inside to be seen from the outside and not be changedeasily and chemically by a slurry or a work material. For example, as anexample of the material for the shielding mechanism 45, PVC is used.

According to the substrate polishing apparatus of such an embodiment, bysuppressing the diffusion of a generated gas at the site of generationand exhausting it effectively, the diffusion of a hazardous substancecan be prevented with a small design change and a reduced load oncustomers. That is, according to this embodiment, even if a hazardousgas is generated between the polishing surface 10 of the polishing table30 and a surface to be polished of a wafer W when the wafer W ispolished, then the top ring cover 36 that covers the outer side of thetop ring 31 can prevent the hazardous gas from diffusing from the siteof generation to the environment.

In such a situation, as shown in FIG. 5, the gas diffusion can beprevented effectively near the site of generation of a hazardous gas.And, this can be implemented by such a comparatively simpleconfiguration as the top ring cover 36 and a large-scaled design changeis not necessitated. Furthermore, by operating the exhaust mechanism 38,air is sucked in through the gap portion 37 between the lower portion ofthe top ring cover 36 and the upper surface of the polishing table 30,the air is exhausted through the pipe 39 provided in the upper portionof the top ring cover 36 and a rising air current is formed between theouter surface of the top ring 31 and the inner surface of the top ringcover 36. Accordingly, a gas can be prevented from leaking out throughthe gap portion 37 in the lower portion of the top ring cover 36 to theenvironment and the gas can be safely exhausted through the pipe 39 inthe upper portion of the top ring cover 36.

Also, by operating the exhaust mechanism 38, air is sucked in throughthe second gap portion 40 between the polishing table 30 and the tablecover 35, the air is exhausted through the second pipe 41 provided inthe lower portion of the table cover 35 and a descending air current isformed between the outer surface of the polishing table 30 and the innersurface of the table cover 35. The table cover 35 that covers the outerside of the polishing table 30 can prevent the diffusion of a hazardousgas to the environment and the gas can be safely exhausted through thesecond pipe 41 in the lower portion of the table cover 35.

Furthermore, in this embodiment, as shown in FIG. 6, when the top ringcover 36 is required (when a hazardous gas is generated), the top ringcover 36 is placed at the used position and the hazardous gas can beprevented from diffusing to the environment. On the one hand, when thetop ring cover 36 is not required (when a hazardous gas is notgenerated), the top ring cover 36 is placed at the non-used position,allowing interference with other components to be prevented.

For example, as shown in FIG. 6A, the top ring cover 36 that covers theentire circumference of the top ring 31 can prevent a hazardous gas fromdiffusing to the environment. In such a situation, the gas can beprevented from diffusing throughout the entire circumference withoutleak.

Alternatively, as shown in FIG. 6B, the top ring cover 36 that partiallycovers the circumference of the top ring 31 can prevent a hazardous gasfrom diffusing to the environment. In such a situation, the diffusion ofa gas can be prevented partially and effectively (only the requiredportion).

Furthermore, in this embodiment, as shown in FIG. 8, once the top ring31 rotates, a rising air current is generated between the outer surfaceof the top ring 31 and the inner surface of the top ring cover 36 by therising air current generating mechanism 43. Providing the rising aircurrent generating mechanism 43 in such a manner can assist in formingthe rising air current between the outer surface of the top ring 31 andthe inner surface of the top ring cover 36.

Also, in such a situation, once the polishing table 30 rotates, adescending air current is generated between the outer surface of thepolishing table 30 and the inner surface of the table cover 35 by thedescending air current generating mechanism 44. Providing the descendingair current generating mechanism 44 in such a manner can assist informing the descending air current between the polishing table 30 andthe table cover 35.

Furthermore, in this embodiment, as shown in FIG. 10, the shieldingmechanism 45 covers the outer side of the top ring cover 36 (the outerside of the top ring cover 36 that covers the outer side of the top ring31) and the outer side of the polishing table 30, so that a functionthat prevents the diffusion of a hazardous gas to the environment can beimproved.

Additionally, in this embodiment, as shown in FIG. 4, because thegas-liquid separating mechanism 42 is provided in the pipe for exhaust39, even if a liquid is mixed into a gas when the gas is sucked inthrough the gap portion 37 between the lower portion of the top ringcover 36 and the upper surface of the polishing table 30, then theliquid can be separated from the gas by the gas-liquid separatingmechanism 42, so that the gas can be appropriately exhausted (separatedfrom the liquid).

Second Embodiment

Next, a characteristic configuration of a substrate polishing apparatusof a second embodiment will be described with reference to the drawings.FIG. 12 is an illustration showing a schematic configuration of thesubstrate polishing apparatus of this embodiment and FIGS. 13 and 14 areillustrations showing a main configuration of the substrate polishingapparatus of this embodiment.

As shown in FIGS. 12 to 14, the substrate polishing apparatus of thisembodiment includes a polishing table 30 having a polishing surface 10in the upper surface, a top ring 31 that holds a wafer W having asurface to be polished in the lower surface and a local exhaustmechanism 135 disposed near the top ring 31. The polishing surface 10includes, for example, a polishing pad. The polishing table 30 rotatesin a predetermined rotation direction (clockwise rotation in FIG. 13)and the top ring 31 presses the surface to be polished of the held waferW (the lower surface in FIGS. 12 and 14) against the polishing surface10 of the polishing table 30 to polish the surface to be polished of thewafer W. Note that the substrate polishing apparatus may include a tablecover that covers the outer side of the polishing table 30 and a topring cover that covers the outer side of the top ring 31.

As shown in FIG. 13, the local exhaust mechanism 135 includes an intakehead 136 disposed near the top ring 31. The intake head 136 is disposedon the downstream side of the top ring 31 in a rotation direction of thepolishing table 30 (on the rotation direction side). Also, the intakehead 136 includes a plurality of inlets 137 arrayed in a radialdirection of the polishing table 30.

As shown in FIG. 14, the inlets 137 of the intake head 136 are connectedto an ejector 138 and by forcing a compressed air to flow into theejector 138, air is sucked in through the inlet 137. The ejector 138 isconfigured so that adjusting a flow rate of the compressed air allows anintake air speed of the inlet 137 to be adjusted. In such a situation,the intake air speed of the inlet 137 of the plurality of inlets 137 onthe outer side in the radial direction is set to be higher than that ofthe inlet 137 on the inner side in the radial direction (see FIG. 13).Note that an intake means from the inlet 137 is not limited to theejector 138, but, for example, a vacuum pump or the like may be used asthe means.

An intake air speed of the intake head 136 is preferably set to behigher than the rotation speed of the polishing table 30. That is, theintake air speed of the intake head 136 is set to be one or more timesthe rotation speed of the polishing table 30 (for example, 1 to 2 m/s).For example, the intake air speed of the intake head 136 is set to be1.2 to 2 times the rotation speed of the polishing table 30. The intakeair speed of the intake head 136 can be set based on the rotation speedof the polishing table and a reference area. The reference area iscalculated from the product of a diameter and a reference height of awafer W. The reference height may be set based on a distance between thetop ring 31 and the intake head 136. For example, the reference heightis set to be 0.3 to 3 times the distance between the top ring 31 and theintake head 136. Also, the reference height may be set based on a heightfrom the polishing surface 10 to an upper end of an opening of the topring 31 (an upper end of a gap of a retainer ring). For example, thereference height is set to be 1 to 3 times the height from the polishingsurface 10 to the upper end of the opening of the top ring 31 (the upperend of the gap of the retainer ring).

Note that, as shown in FIG. 12, the local exhaust mechanism 135 includesa pipe for exhaust 140 connected to an exhaust mechanism 139. Note thatthe pipe for exhaust 140 may be connected to a duct having an exhaustfunction, or include a blower driven by an electric motor or the like.Also, in the pipe for exhaust 140, a gas-liquid separating mechanism 141is provided. In such a situation, because the gas-liquid separatingmechanism 141 is provided in the pipe for exhaust 140, even if a liquidis mixed into a gas when the gas is sucked in, then the gas-liquidseparating mechanism 141 can separate the liquid from the gas, and thegas sucked in (separated from the liquid) can be appropriatelyexhausted. Note that between the gas-liquid separating mechanism 141 andthe exhaust mechanism 139, a damper may be provided.

According to the substrate polishing apparatus of such an embodiment ofthe invention, even if a hazardous gas is generated when a wafer W ispolished, the gas diffusion can be effectively prevented near the siteof generation of the hazardous gas.

That is, in this embodiment, even if a hazardous gas is generated when awafer W is polished, the intake head 136 disposed near the top ring 31can effectively suck in the gas. In such a situation, because the intakehead 136 is disposed on the downstream side in a rotation direction ofthe polishing table 30 (on the rotation direction side), a gas made toflow by an air current (swirl flow) generated from rotation of thepolishing table 30 can be effectively sucked in. As described, such acomparatively simple configuration as the intake head 136 caneffectively prevent the gas diffusion near the site of generation of ahazardous gas without requiring a large-scaled design change.

A speed at which a gas is made to flow by the air current (swirl flow)generated from the rotation of the polishing table 30 is thought to beabout equal to (or not greater than) the rotation speed of the polishingtable 30. In such a situation, the intake air speed of the intake head136 is set to be higher than the rotation speed of the polishing table30, so that a gas made to flow by the air current (swirl flow) generatedfrom the rotation of the polishing table 30 can be preferably sucked independing on the speed at which the gas is made to flow.

Also, in this embodiment, the plurality of inlets 137 of the intake head136 can suck in a hazardous gas generated when a wafer W is polished.Because the rotation speed of the polishing table 30 is higher on theouter side in the radial direction than on the inner side, the speed atwhich a gas is made to flow by the air current (swirl flow) generatedfrom the rotation of the polishing table is thought to be higher on theouter side in the radial direction than on the inner side (there is adifference along the radial direction). In such a situation, theplurality of inlets 137 is arrayed in the radial direction of thepolishing table 30 and the intake air speed of the inlet 137 on theouter side in the radial direction is set to be higher than that on theinner side, so that a gas made to flow by the air current (swirl flow)generated from the rotation of the polishing table 30 can be preferablysucked in depending on a difference in speed at which the gas is made toflow (difference along the radial direction).

Conventionally, an exhaust velocity around a polishing table is set tobe an approximate speed at which a gas is not curled up by an aircurrent generated from rotation of the polishing table and can besmoothly exhausted (for example, about 0.3 m/s). In contrast, a rotationspeed of the polishing table (speed in the circumferential direction) isusually 1 to 2 m/s. In such a conventional exhaust velocity, if ahazardous gas is generated on polishing, then the gas diffuses over thepolishing table at a rotation speed of the polishing table (the speedhigher than the exhaust velocity) and it may become easy for the gas todiffuse evaporatively from the polishing table surface. Additionally,the conventional substrate polishing apparatus adopts, for example, aconfiguration in which a cover is provided around the polishing tableand air is exhausted from the circumference of the polishing tablethrough a usual exhaust line, but if, by any chance, the usual exhaustline stops functioning, exhaust may be not carried out. In contrast, inthis embodiment, the ejector 138 is adopted as the local exhaustmechanism 135, so that a suction function higher than the conventionalfunction (exhaust is performed by the usual exhaust line) can beprovided. Furthermore, in this embodiment, as long as the ejector 138 issupplied with a compressed air, even if the usual exhaust line stopsfunctioning, then a local exhaust above the polishing table can beimplemented, so that safety around the equipment can be ensured. Notethat, as shown in FIG. 15, the ejector 138 may be provided at a positionseparated from the intake head 136.

Note that, in the above description, an example has been described inwhich the intake air speed of the intake head 136 is set to be higherthan the rotation speed of the polishing table 30, but the intake airspeed of the intake head 136 may be set to be slightly lower than therotation speed of the polishing table 30. That is, the intake air speedof the intake head 136 may be set to be one or less times the rotationspeed of the polishing table 30. For example, the intake air speed ofthe intake head 136 may be set to be 0.8 times the rotation speed of thepolishing table 30.

Third Embodiment

This embodiment relates to an exhaust volume of a wafer polishing roomin a CMP apparatus and a polishing pad temperature. Temperatures of apolishing pad surface and a polishing solution that covers the padsurface (hereinafter, called a “slurry”) increase because of thermalenergy input caused by a polishing load. This embodiment relates to amechanism/apparatus that lowers, or manages and controls thesetemperatures.

Conventionally, in order to remove heat from the pad surface and theslurry to lower the temperature, for example, (1) a mechanism/apparatusin which a cooling plate is laid on the pad surface to remove heat byheat conduction, and (2) a mechanism/apparatus in which a dry gas issprayed onto the pad surface to remove heat by latent heat ofvaporization have been adopted.

For methods to increase a polishing rate, it is thought, for example,that a polishing surface pressure is increased, or a relative speed ofthe polishing surface is increased. However, doing so increases lossenergy due to friction of the polishing surface and the energy is inputto the polishing pad, the slurry, a wafer of a product to be polishedand a top ring that holds the wafer, causing respective temperatures toincrease.

As for the slurry, it can be expected that the polishing rate increasesdue to polishing (etching) performed by a chemical performance of theslurry provided from an increase in temperature. But, if the temperaturebecomes too high, the performance of the slurry deteriorates and theproper polishing performance may not be exerted. Also as for the pad,when the temperature goes high, a hardness and a Young's modulus of thepad lower, which may cause deterioration of a flatness of the wafersurface to be polished of a product to be polished. Also, as for the topring that holds a wafer, if an increase in temperature is high, there isan effect on a mechanism that presses the wafer against the pad.Therefore, it has been strongly desired to be able to manage and controlan increase in temperature caused from polishing.

Therefore, the contact heat conduction system (1) and the latent heat ofvaporization system by spraying a dry gas (2) pointed out previouslyhave been developed.

However, in the conventional cooling plate system (1), the cooling platecontacts with the pad and the slurry in contact with a wafer to bepolished. Thus, contamination from the cooling plate (ions, particles)is worried about, and a cleaning apparatus for a coating portion and acontact portion becomes necessary. Furthermore, also there is concernover a scratch problem with a wafer surface caused from dropping of theslurry that adheres to the cooling plate and a cleaning apparatus forthe whole cooling plate becomes necessary. Accordingly, the apparatusitself may become large-scaled. Additionally, because heat is removed bycontact heat conduction, the system is proportional to a contact areaand a temperature difference, accordingly a wide area and a largetemperature difference become necessary. But, because, in a polishingpad surface, a top ring that holds a wafer, a dresser that dresses apad, a slurry nozzle that supplies a slurry, an atomizer nozzle thatwashes the pad surface (high-pressure purified water shower nozzle), orthe like are provided, the contact area cannot be ensured as intended.

Thus, a system in which a dry gas (air or N₂) is sprayed onto a wet padsurface to remove heat by latent heat of vaporization (2) has also beenadopted to some degree. However, the sprayed dry gas causes a slurry tofly apart, so that a component of the slurry effective for polishing maybe decreased. Also, the slurry that flies apart adheres to theenvironment and the adherent slurry may drop to cause a scratch problemwith a wafer surface. As described, the conventional system (2) has aproblem difficult to solve and lacks a general versatility, thus itsapplicable scope has been narrow.

A substrate polishing apparatus of this embodiment includes a substrateholding portion that holds a substrate and presses the substrate againsta polishing table to polish the substrate, a pad cooling nozzle forcooling a polishing pad that polishes a substrate, and a local exhaustmechanism whose intake head is disposed near the pad cooling nozzle, inwhich the intake head is disposed on the downstream side of the padcooling nozzle in a rotation direction of the polishing table.

This configuration provides a substrate polishing apparatus (CMPapparatus) in which a hazardous gas and a defect source generated on thepolishing table are positively collected and removed, and simultaneouslythe polishing pad is cooled by the pad cooling nozzle. In such asituation, the local exhaust mechanism can locally exhaust a gas sprayedfrom the pad cooling nozzle.

Also, the substrate polishing apparatus of this embodiment furtherincludes a second local exhaust mechanism whose second intake head isdisposed near the substrate holding portion, in which the second intakehead may be disposed on the downstream side of the substrate holdingportion in the rotation direction of the polishing table.

According to this configuration, the second local exhaust mechanism canexhaust a hazardous gas and a defect source generated near the substrateholding portion.

According to this configuration, the problem with the conventional drygas spraying system (2) can be solved, the phenomenon of latent heat ofvaporization can be utilized, heat can be removed from the polishingpad, a slurry that covers the polishing pad surface and a top ring thatholds a wafer and an increase in their temperatures can be managed andcontrolled. Therefore, a good flatness of a surface to be polished canbe provided and a polishing process can be implemented in a temperatureregion where a performance of the slurry can be brought out. Thus, theproductivity of the CMP apparatus can be improved.

Next, a characteristic configuration of a substrate polishing apparatusof a third embodiment will be described with reference to the drawings.FIGS. 16 and 17 are illustrations showing a main configuration of thesubstrate polishing apparatus of this embodiment.

As shown in FIGS. 16 and 17, the substrate polishing apparatus of thisembodiment includes a polishing table 30 having a polishing surface 10in the upper surface, a top ring 31 that holds a wafer W having asurface to be polished in the lower surface and a local exhaustmechanism 135 disposed near the top ring 31. The polishing surface 10includes, for example, a polishing pad. The polishing table 30 rotatesin a predetermined rotation direction (clockwise rotation in FIG. 16)and the top ring 31 presses the surface to be polished of the held waferW (lower surface in FIG. 17) against the polishing surface 10 of thepolishing table 30 to polish the surface to be polished of the wafer W.Note that the substrate polishing apparatus may further include a tablecover that covers the outer side of the polishing table 30 and a topring cover that covers the outer side of the top ring 31.

As shown in FIG. 16, on the downstream side of the top ring 31, a padcooling nozzle 142 for cooling the polishing pad (polishing surface 10)is provided. A gas sprayed from the pad cooling nozzle 142 (cooling gas)cools the polishing surface 10. On the downstream side of the padcooling nozzle 142, a local exhaust mechanism 135 is provided. Thislocal exhaust mechanism 135 can locally exhaust the gas sprayed from thepad cooling nozzle 142.

An intake head 136 of the local exhaust mechanism 135 is disposed on thedownstream side of the pad cooling nozzle 142 (and the top ring 31) in arotation direction of the polishing table 30 (on the rotation directionside). Also, the intake head 136 includes a plurality of inlets 137arrayed in a radial direction of the polishing table 30.

As shown in FIG. 17, the inlets 137 of the intake head 136 are connectedto an ejector 138, and by making a compressed air to flow into theejector 138, air is sucked in through the inlets 137. The ejector 138 isconfigured so that adjusting a flow rate of the compressed air allows anintake air speed of the inlet 137 to be adjusted. In such a situation,the intake air speed of the inlet 137 of the plurality of inlets 137 onthe outer side in the radial direction is set to be higher than that ofthe inlet 137 on the inner side in the radial direction (see FIG. 16).Note that an intake means from the inlet 137 is not limited to theejector 138, but, for example, a vacuum pump or the like may be used asthe means.

An intake air speed of the intake head 136 is preferably set to behigher than a rotation speed of the polishing table 30. That is, theintake air speed of the intake head 136 is set to be one or more timesthe rotation speed of the polishing table 30 (for example, 1 to 2 m/s).For example, the intake air speed of the intake head 136 is set to be1.2 to 2 times the rotation speed of the polishing table 30. The intakeair speed of the intake head 136 can be set based on the rotation speedof the polishing table and a reference area. The reference area iscalculated from the product of a diameter of a wafer W and a referenceheight. The reference height may be set based on a distance between thetop ring 31 and the intake head 136. For example, the reference heightis set to be 0.3 to 3 times the distance between the top ring 31 and theintake head 136. Also, the reference height may be set based on a heightfrom the polishing surface 10 to the upper end of an opening of the topring 31 (the upper end of a gap of a retainer ring). For example, thereference height is set to be 1 to 3 times the height from the polishingsurface 10 to the upper end of the opening of the top ring 31 (the upperend of the gap of the retainer ring).

Note that, as shown in FIG. 18, the local exhaust mechanism 135 may bedisposed not only on the downstream side of the top ring 31 but near thetop ring 31. That is, two local exhaust mechanisms 135 (the localexhaust mechanism 135 on the downstream side of the top ring 31 and thelocal exhaust mechanism 135 near the top ring 31) may be provided. Insuch a situation, the local exhaust mechanism 135 on the downstream sideof the top ring 31 can locally exhaust the gas sprayed from the padcooling nozzle 142 and the local exhaust mechanism 135 near the top ring31 can exhaust a reaction gas of a material to be polished and theslurry.

What is claimed is:
 1. A substrate polishing apparatus, comprising: arotating polishing table comprising a polishing face on the rotatingpolishing table; a substrate holding portion that holds a substrate andpresses the substrate against the polishing table to polish thesubstrate; and a local exhaust mechanism configured to suck a gas,wherein the local exhaust mechanism comprises an intake head disposednear the substrate holding portion, wherein the intake head is disposedon a downstream side of the substrate holding portion in a rotationdirection of the polishing table, wherein the intake head comprises atleast one inlet whose opening is facing upward, and wherein a bottom endof an ejector is vertically connected to an inlet of the intake head,and the gas moves upward into the local exhaust mechanism.
 2. Thesubstrate polishing apparatus according to claim 1, wherein an intakeair speed of the intake head is set to be higher than a rotation speedof the polishing table.
 3. The substrate polishing apparatus accordingto claim 2, wherein the intake head comprises a plurality of inletsarrayed in a radial direction of the polishing table, an intake airspeed of the inlet of the plurality of inlets on the outer side in aradial direction is set to be higher than that on the inner side in theradial direction.
 4. The substrate polishing apparatus according toclaim 1, wherein the gas is a hazardous gas generated when the wafer ispolished, or the gas is a gas made to flow by an air current swirl flowgenerated from rotation of the polishing table.
 5. The substratepolishing apparatus according to claim 1, wherein the intake head isarranged above the polishing face.
 6. A substrate polishing apparatus,comprising: a rotating polishing table comprising a polishing face onthe rotating polishing table; a substrate holding portion that holds asubstrate and presses the substrate against a polishing table to polishthe substrate; a pad cooling nozzle for cooling a polishing pad thatpolishes the substrate, the pad cooling nozzle being configured to spraya cooling gas, wherein an output of the pad cooling nozzle is directeddownstream in a rotation direction; and a local exhaust mechanismconfigured to suck the cooling gas, wherein the local exhaust mechanismcomprises an intake head, the output of the pad cooling nozzle facingthe local exhaust mechanism, wherein the intake head is disposed on adownstream side of the pad cooling nozzle in a rotation direction of thepolishing table, and wherein an ejector is connected to the intake head.7. The substrate polishing apparatus according to claim 6, comprising: asecond local exhaust mechanism comprises a second intake head isdisposed near the substrate holding portion, wherein the second intakehead is disposed on the downstream side of the substrate holding portionin the rotation direction of the polishing table.
 8. The substratepolishing apparatus according to claim 6, wherein the gas is a hazardousgas generated when the wafer is polished, or the gas is a gas made toflow by an air current swirl flow generated from rotation of thepolishing table.
 9. The substrate polishing apparatus according to claim6, wherein the intake head is arranged above the polishing face.
 10. Asubstrate processing apparatus, comprising: a polishing portion coveredby a partition wall; a cleaning portion; and a transport mechanism thattransports a substrate between the polishing portion and the cleaningportion; wherein the polishing portion comprises: a polishing tablehaving a polishing surface in an upper surface; a substrate holdingportion that holds a substrate having a surface to be polished in alower surface and presses the surface to be polished of the substrateagainst the polishing surface of the polishing table to polish thesurface to be polished of the substrate; and a shielding mechanismlocated between the polishing table and the partition wall, theshielding mechanism covering an outer side surface of the substrateholding portion and an outer side surface of the polishing table,wherein the shielding mechanism includes an opening portion on a sidewall for allowing the substrate to pass through the shielding mechanism,wherein a top of the opening portion is higher than the polishing table,and a bottom of the opening portion is lower than the polishing surfaceof the polishing table.
 11. The substrate processing apparatus accordingto claim 10, wherein the shielding mechanism is one of a vinyl curtain,panels and bellows.